Dibenzalacetone derivatives are typically prepared by the reaction of two molecules of a benzaldehyde derivative with one molecule of acetone usually under basic conditions. Aldol reactions of this type are known and specifically the reaction of methyl p-formylbenzoate with acetone to provide 1,5-bis-(4'-carbomethoxyphenyl)-1,4-pentadien-3-one has been previously described by Blount and Zoeller in U.S. Pat. Nos. 5,025,086, 4,965,399, and 4,923,958.
Hydrogenation of the dibenzalacetone backbone (the pentadienone unit) with either homogeneous or heterogeneous catalysts provides for a 3-pentanone or 3-pentanol structure which is now of particular interest for developing polyfunctional derivatives which can be useful in the preparation of coatings, particularly as crosslinkers. Only in U.S. Pat. No. 5,025,086 does Blount and Zoeller describe a hydrogenation process to prepare the cycloaliphatic derivatives of dibenzalacetone; more specifically 1,5-bis-(4'-carbomethoxycyclohexyl)-3-pentanol and 1,5-bis-(4'-carbomethoxycyclohexyl)-3-pentanone.
In the cited references, the uses of the dibenzalacetone derivatives were limited to incorporation into polyester resins with other polyols and polybasic acids commonly known in the art. These dibenzalacetone derivatives cited were not, however, further developed into polyfunctional derivatives which could be used directly as crosslinkers and the types of crosslinkers which could be useful as crosslinkers were not disclosed.
The trifunctional amine derivatives described in the present invention are particularly of interest since the commercial availability of trifunctional amines which contain only primary amines is quite limited. One such trifunctional primary amine is tris-(2-aminoethyl)amine, also refered to as TREN.RTM. amine, available from Pressure Chemical Company. This trifunctional amine is quite expensive for most applications used in coatings.
Another use of the dibenzalacetone derivatives described within are for the preparation of poly beta-hydroxyethylamides. Beta-hydroxyethylamides are known and used in the art, particularly in powder coatings. One such commercial product is Primid XL-552.RTM. crosslinker available from EMS-Chemie AG.